Optocardiography and Electrophysiology Studies of Ex Vivo Langendorff-perfused Hearts
November 7th, 2019
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The objective of this study was to establish a method for investigating cardiac dynamics using a translational animal model. The described experimental approach incorporates dual-emission optocardiography in conjunction with an electrophysiological study to assess electrical activity in an isolated, intact porcine heart model.
Overview
This study presents a method for investigating cardiac dynamics using an isolated porcine heart model. The approach combines electrophysiological studies with dual-emission optocardiography to assess cardiac electrical activity.
Key Study Components
Area of Science
- Cardiac dynamics
- Electrophysiology
- Optical mapping
Background
- Cardiovascular malfunction is a leading cause of death globally.
- The isolated heart model provides insights into human cardiac dynamics.
- This methodology is applicable in disease modeling, pharmacology, and toxicology studies.
- Technical challenges exist compared to smaller animal models.
Purpose of Study
- To establish a reliable method for studying cardiac dynamics.
- To evaluate the effects of various substances on cardiac electrophysiology.
- To demonstrate the feasibility of using an isolated porcine heart model.
Methods Used
- Isolation of the heart with intact ascending aorta.
- Perfusion with ice-cold cardioplegia and modified Krebs-Henseleit medium.
- Electrophysiological pacing and recording of ECG.
- Optical mapping of transmembrane voltage and intracellular calcium.
Main Results
- Successful isolation and perfusion of the porcine heart.
- Establishment of pacing thresholds and refractory periods.
- Acquisition of optical signals during various cardiac rhythms.
- Demonstration of the methodology's applicability in cardiac research.
Conclusions
- The isolated porcine heart model is effective for studying cardiac dynamics.
- This method can enhance understanding of cardiac electrophysiology.
- Visual demonstrations can aid in reproducing the experimental setup.
Frequently Asked Questions
What is the significance of using a porcine heart model?
The porcine heart model closely resembles human cardiac physiology, making it valuable for translational research.
How does dual-emission optocardiography work?
It allows simultaneous mapping of transmembrane voltage and intracellular calcium, providing comprehensive insights into cardiac function.
What are the challenges of this methodology?
The protocol is technically challenging and requires careful setup to ensure successful isolation and perfusion of the heart.
Can this method be used for pharmacological studies?
Yes, it is applicable for evaluating the effects of drugs on cardiac dynamics and electrophysiology.
What precautions should be taken during the experiment?
Ensure no air enters the vasculature during perfusion and monitor for arrhythmias throughout the study.
How is the pacing threshold determined?
By applying a series of stimulus impulses and identifying the minimum current required to achieve consistent capture.
Executive Industry Relevance
This method enables translational cardiovascular research by combining electrophysiology and optical mapping in an ex vivo porcine heart model, offering a physiologically relevant system for preclinical evaluation of cardiac safety and efficacy. It supports mechanistic de-risking of therapeutic candidates by providing quantitative, high-resolution data on electrophysiological and calcium handling parameters. The approach bridges the gap between small-animal models and human physiology, improving predictive confidence in lead optimization and safety pharmacology workflows.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of cardiac conduction system function and action potential morphology under controlled conditions.
- Scientific Value: Supports functional validation of ion channel and calcium handling targets through direct measurement of electrophysiological parameters.
- Operational Value: Provides reproducible metrics for assessing compound effects on ventricular effective refractory period and Wenckebach cycle length.
Screening & Assay Development
- Scientific Value: Generates quantitative optical signals for transmembrane voltage and intracellular calcium, enabling ratiometric analysis of excitation-contraction coupling.
- Operational Value: Delivers standardized readouts such as action potential duration, calcium transient coupling time, and restitution curves for compound screening.
- Operational Value: Facilitates assay readiness through stable sinus rhythm and defined pacing protocols after system equilibration.
Translational & Preclinical Research
- Scientific Value: Models human-relevant cardiac physiology in a larger mammalian system, enhancing translational validity of preclinical findings.
- Scientific Value: Enables detection of pro-arrhythmic liabilities such as cardiac alternans and ventricular fibrillation under pacing stress.
- Operational Value: Supports longitudinal assessment of cardiac function with post-experiment tissue preservation for histology or gene expression.
Pipeline & Workflow Integration
The method fits within the discovery-to-preclinical continuum, supporting hypothesis testing in early discovery, assay development in screening, and mechanistic evaluation in translational research.
- Discovery Biology: Enables pathway clarification and target validation through direct measurement of electrophysiological and calcium handling dynamics.
- Screening: Provides assay-ready, reproducible optical and electrophysiological outputs for evaluating compound effects on cardiac electrophysiology.
- Analytics: Yields quantitative metrics including ventricular effective refractory period, sinus node recovery time, and action potential duration for comparative analysis.
- Translational Research: Connects discovery findings to preclinical continuity via disease-relevant cardiac physiology in a porcine model.
- Enterprise Reuse: Establishes a reusable platform for cardiac safety pharmacology, mechanistic de-risking, and lead optimization campaigns.
Operational & Enterprise Impact
- Scientific Value: Enhances predictive confidence by reducing mechanistic ambiguity in cardiac electrophysiology and calcium handling.
- Operational Value: Delivers standardized, high-fidelity measurements through simultaneous electrophysiology and dual-emission optocardiography.
- Strategic Value: Improves go/no-go decisions by identifying pro-arrhythmic risk early in the discovery pipeline.
- Portfolio Impact: Enables risk-adjusted prioritization of compounds based on quantitative electrophysiological and calcium transient parameters.
Implementation Considerations
- Requires expertise in cardiac isolation, Langendorff perfusion, electrophysiology stimulation, and optical mapping techniques.
- Dependent on specialized instrumentation including differential bioamplifiers, pacing stimulators, high-speed cameras, and LED illumination systems.
- Necessitates cross-team standardization of perfusate composition, temperature control, and dye loading protocols for reproducible results.
- Involves adaptation considerations for different species, heart sizes, and disease models when translating the protocol.
- Includes practical limitations such as technical complexity in bubble-free perfusion and motion artifact minimization during optical acquisition.
Biopharma FAQs
Why does ventricular effective refractory period measurement matter for target validation?
Measuring the ventricular effective refractory period helps assess the compound's impact on cardiac repolarization and arrhythmia susceptibility, providing a functional readout for ion channel target validation.
How does S1-S2 pacing train isolation of the pacing threshold support discovery pipeline decisions?
Determining the pacing threshold through S1-S2 trains identifies the minimum stimulus required for capture, enabling consistent electrophysiological pacing and reliable compound effect assessment in screening workflows.
What do quantitative optical mapping measurements of transmembrane voltage and calcium enable?
Simultaneous optical mapping of voltage and calcium provides ratiometric data on excitation-contraction coupling, action potential duration, and calcium transient kinetics, supporting mechanistic de-risking of cardiac liabilities.
Why do replication requirements in Langendorff perfusion matter for cross-functional collaboration?
Reproducible heart stabilization at 70 bpm and consistent flow rates ensure reliable data generation across experiments, enabling comparable results between discovery, toxicology, and pharmacology teams.
What statistical analysis capabilities are required before implementing restitution curve generation?
The ability to plot action potential duration or calcium transient recovery against pacing cycle length is required to generate electrical and calcium restitution curves, which help assess alternans and arrhythmia risk under dynamic pacing conditions.
Chapters in this video
0:05
Title
1:02
Heart Excision and Langendorff Perfusion
2:42
Electrophysiology Study
5:17
Transmembrane Voltage and Intracellular Calcium Optical Mapping
6:55
Cleanup
7:20
Results: Representative Optical Data from Langendorff-Perfused Model Hearts
8:59
Conclusion
